Tool for truing crank shafts



Sept. 13, 1932. 1', CRUTE 1,876,621

TOOL FOR TRUING CRANK SHAFTS Filed Nov. 4. 1950 A TTORNEYJ INVENTOR.

Patented Sept. 13, 1932 HIT TATES PATENT) oFFIcE JOSEPH THOMAS CRUTE, OF VIRGILINA, VIRGINIA, ASSIGNOR OF ONE-HALF T MARVIN A. GOODE, OF VIRGILIN A, VIRGINIA.

TOOL FOR TRUING CRANK SI-IAFTS This invention relates to a tool for truing the crank shafts of engines and it has for its object to provide an improved device of this character, constructed in such manner as to render it possible to use the same upon crank shafts without removing the latter from the engines in which they are located.

It is common practice, in the truing of crank shafts, to use a two-part hinged clamp carrying a cutting tool, said clamp being clamped about the part to be trued and rotated therearound to bring the crank shaft to truly circular formation. However, it has been necessary, heretofore, to remove the 13 crank shafts from the engines in order to accomplish this work. By my approved arrangement I am able to accomplish this result without the necessity of removing the crank shaft from the engine.

In the accompanying drawing:

Figure 1 is a plan view of a two-part clamp, hereinafter described;

Figure 2 is an end elevation thereof;

Figure 3 is an end elevation like Figure 2, with a ratchet wrench in place on the clamp; and

Figure l is a detailed view of the cutting blade or scraper, hereinafter described.

Like numerals designate corresponding parts in all the figures of the drawing.

By referring to the drawing, it will be seen that the device of the present invention comprises a two-part clamp consisting of the sections 5 and 6, which are hingedly connected to each other at 7 and which sections are adapted to be held in closed position by a pin 8 which traverses ears formed upon the two sections. At some suitable point upon the clamp a surface is formed that is adapted to receive a ratchet wrench 9, having a handle 10. In the particular form of the invention that I have chosen for purposes of illustration, this ratchet wrench receiving surface consists of projections 5a6a formed upon the sections 5 and 6 of the clamp, respectively, said projections having the angular faces -66. The section 5 carries a cutting blade or scraper 11 which scrapes or cuts the surface of the crank shaft indicated at 12 to 50 bring the same to a truly circular form as Application filed. November 4, 1930. Serial No. 493,410.

the tool is rotated around the crank shaft by the action of the ratchet wrench. I

As will be seen from an inspection of Figure 4, the outer portion of the knife is cut away, as indicated at 13, so that the presence of the knife will not interfere with the placement of the ratchet wrench on the angular extensions 5a6a.

While I have, for purposes of illustration, shown the angular surface upon the end of 0- the clamp sections, it is apparent that suitably formed surfaces may be provided at an intermediate point in the length of the clamp for the reception of a ratchet wrench. By virtue of the arrangement shown and described, it is possible to turn the tool through the bottom of a crank case after the cover plate has been removed without removing the crank shaft from the engine. This will save an enormous amount of work, because it requiresmuch more time to dismantle an engine to remove the crank shaft than it does to actually true up the crank shaft after it has been made accessible. It will be noted that the mean diameter of the angular part formed by the extensions 52 and 62 is materially less than the diameter of the body portion comprising the parts 5 and 6. This renders it possible to use a wrench having a materially smaller head than would have to be used if the wrench were placed directly upon the parts 5 and 6. This is of great importance when working in a restricted space, such as the interior of a crank case.

It is to be understood that the invention is not limited to the precise construction set forth but that it includes within its purview whatever changes fairly come within the terms or the spirit of the appended claim.

I-Iaving described my invention, what I claim is:

A crank pin truing tool of the character described comprising a body portion made of two separable halves adapted to complementally embrace a crank pin, means for holding the free edges of said halves together, an elongated cutting or scraping tool carried by one of said halves and extending in parallelism with the axes of the crank pin to be trued, and an angular extension upon the ids" end of each of said halves, said extensions coinplementally forming a Wrench-receiving surface having a mean diameter that is Ina terially less than the diameter of the body portion, said tool extending substantially throughout the combined length of the body portion and angular extensions and being cut away at the point Where it passes through said extensions so as not to extend beyond the surface thereof.

In testimony whereof I aflix my signature.

JOSEPH THOMAS CRUTE. 

